sigma flash

I would really like to understand the term ‘’brother/sister’’ in Transformers IDW G1 canon. Transformers there were either forged [an energy pulse from Vector Sigma would flash across the world, igniting a hot spot where new sparks would emerge from the planet.— source] or constructed cold [sparks generated by the Matrix, which then housed in pre-constructed bodies.]. They have no parents, so on what basis two Cybertronians called each other siblings?

They already had term for very close friendship, and those who called each other Amica had a different dynamic to those calling each other siblings. Sideswipe and Sunstreaker, Minimus and Dominus, Tracks and Needlenose, they all shared the same dynamic of (dysfunctional) family.

And why only dysfunctional family dynamic had been shown? Was there no amicable siblings’ relationship amongst Cybertronians in IDW Transformers?